1. Field of the Invention
This invention relates to apparatus for feeding a sheet of paper one by one from a stack of sheets of paper, and, in particular, to a sheet feeding apparatus suitable for use in an imaging system, such as a printer, facsimile machine, or copier.
2. Description of the Prior Art
An imaging system using cut sheets of paper for forming an image thereon typically includes a paper feeding section where a number of cut sheets of paper are stored in the form of a stack and the sheets of paper are supplied one by one toward an imaging section. Such an imaging system includes a printer, facsimile machine, or copier, and in such a case, one or more of registration rollers are provided for synchronizing the operation at the imaging section and the sheet feeding operation. For example, in the case of a copier, a photosensitive drum is typically used to form thereon a toner image, which is then transferred to a cut sheet of paper supplied from the paper feeding section. In this case, a cut sheet of paper supplied from a stack of cut sheets of paper is once halted at the registration rollers, which are driven to rotate to advance the cut sheet of paper to be brought into contact with the photosensitive drum, thereby causing the toner image to be transferred from the drum to the cut sheet of paper.
In some cases, the distance from the paper storing section where a number of cut sheets of paper are stored in the form of a stack to the registration rollers is relatively long, so that, in the case of a continuous paper feeding operation, it is often encountered that the next following cut sheet of paper partly or wholly stays in a travelling path between the paper storing section and the registration rollers when the preceding cut sheet of paper is jammed. If this happens, the operator is required to remove not only the jammed cut sheet of paper, but also the next following cut sheet of paper which is partly or wholly present in the travelling path between the paper storing section and the registration rollers. In this case, the operator has to open an outer cover of the imaging system so as to access to the travelling path in which the sheet of paper stays for manual removal thereof. This is quite disadvantageous.
Moreover, in the case where the cut sheet of paper used is relatively large in size, e.g., A3 or B4 size, it is very likely that the leading portion of the cut sheet of paper has already reached at the image transfer station when the cut sheet of paper has come to a halt due to jamming of the preceding cut sheet of paper. In this case, on the cut sheet of paper is partly formed a toner image which has not yet been permanently fixed to the cut sheet of paper, so that when the cut sheet of paper is pulled out of the system, the toner could be removed from the cut sheet of paper being pulled out to smear the registration rollers, paper feed rollers, guide plates, or any other associated elements in the system.